sched/wait: Introduce wait_on_bit_timeout() (44fc0e5e) · Commits · 戴 / test

Add a new wait_on_bit_timeout() helper, basically the same as wait_on_bit() except that it also takes a 'timeout' parameter. All the building blocks like bit_wait_timeout() and out_of_line_wait_on_bit_timeout() are already in place so the addition is rather simple. Signed-off-by:

Johan Hedberg <johan.hedberg@intel.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Cc: davem@davemloft.net Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1422616476-2917-2-git-send-email-johan.hedberg@gmail.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

include/linux/wait.h

+26 −0

Original line number	Diff line number	Diff line
		@@ -989,6 +989,32 @@ wait_on_bit_io(void *word, int bit, unsigned mode)
		mode);
		}

		/**
		* wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses
		* @word: the word being waited on, a kernel virtual address
		* @bit: the bit of the word being waited on
		* @mode: the task state to sleep in
		* @timeout: timeout, in jiffies
		*
		* Use the standard hashed waitqueue table to wait for a bit
		* to be cleared. This is similar to wait_on_bit(), except also takes a
		* timeout parameter.
		*
		* Returned value will be zero if the bit was cleared before the
		* @timeout elapsed, or non-zero if the @timeout elapsed or process
		* received a signal and the mode permitted wakeup on that signal.
		*/
		static inline int
		wait_on_bit_timeout(void *word, int bit, unsigned mode, unsigned long timeout)
		{
		might_sleep();
		if (!test_bit(bit, word))
		return 0;
		return out_of_line_wait_on_bit_timeout(word, bit,
		bit_wait_timeout,
		mode, timeout);
		}

		/**
		* wait_on_bit_action - wait for a bit to be cleared
		* @word: the word being waited on, a kernel virtual address

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